CD44

MIM.107269

Tuesday 17 June 2003

Definition: CD44 is a well characterized cellular adhesion molecule involved in several human malignancies. It is encoded by a gene located at 11p12-13.

Functions

CD44 binds hyaluronan. Mucin-like glycoproteins, such as heparan sulfate, serve as ligands for the leukocyte adhesion molecule called CD44. These glycoproteins are found in the extracellular matrix and on cell surfaces.

CD44 is expressed by lymphoid cells, and is involved in the extravasation of lymphoid cells, it does not appear to be involved in the sequestration or transport of HA by lymphatic vessels.

CD44 is a widely distributed integral membrane glycoprotein, which is expressed as a multitude of isoforms generated by alternative splicing of at least 10 different variant exons and post-translational modifications.

CD44 is currently thought to be the principal cell surface receptor for hyaluronate (hyaluronic acid), the major component of the extracellular matrix.

The adhesion molecule CD44 (CD44s; CD44H) and its isoforms (CD44v3-6 and v9) are preferentially expressed by different cell types. These transmembrane glycoproteins are involved in cell-cell and cell-matrix interactions and in cell trafficking and, thus, may play a role in tumor metastasis and/or local invasion.

Pathology

The expression pattern of CD44s and variant isoforms, particularly CD44v6 and CD44v9, of some neoplasms, including soft tissue tumors, correlates with clinical course and outcome.

Overexpression of isoform CD44v6 correlates with amplification at 11p12-13 in diffuse-type gastric adenocarcinomas.